| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.838 | 114 |
| 2015 | 1.463 | 111 |
| 2014 | 2.336 | 102 |
| 2013 | 3.663 | 73 |
| 2012 | 4.774 | 63 |
| 2011 | 4.167 | 71 |
| 2010 | 3.252 | 93 |
| 2009 | 2.736 | 119 |
| 2008 | 4.866 | 82 |
| 2007 | 3.949 | 109 |
| 2006 | 2.859 | 127 |
| 2005 | 2.229 | 130 |
| 2004 | 2.291 | 119 |
| 2003 | 2.478 | 119 |
| 2002 | 2.758 | 120 |
| 2001 | 3.317 | 119 |
| 2000 | 6.133 | 86 |
| 1999 | 8.692 | 61 |
| 1998 | 10.7 | 55 |
| 1997 | 10.108 | 60 |
| 1996 | 13.508 | 48 |
| 1995 | 15.75 | 36 |
| 1994 | 18.917 | 27 |
| 1993 | 19.333 | 28 |
| 1992 | 19.915 | 24 |
| 1991 | 20.667 | 28 |
| 1990 | 19.517 | 26 |
| 1989 | 17.141 | 25 |
| 1988 | 17.325 | 17 |
| 1987 | 15.333 | 20 |
| 1986 | 15.5 | 21 |